Study of ethidium bromide interaction peculiarities with DNA

Abstract

The helix-coil transition of DNA-ethidium bromide complexes in an interval of ionic strength of 2.0 x 10 −3 M ≤ µ Na+ ≤ 2.0 × 10 −2 M has been investigated. It has been revealed that at the certain high ligand-DNA ratios (r b ) the transition interval of the complex -(∆T) becomes equal to that of DNA itself (∆T 0 ). It has been shown that the values of r b at which δ∆T=∆T-∆T 0 =0 depends on ionic strength of a solution. Further increasing of ligand concentration leads to its conversion from stabilizer into the destabilizer of the double-stranded DNA.

The binding of ethidium bromide with DNA: interaction with single- and double-stranded structures

“…Therefore, EtBr, as well as AMD, will bind with ss-DNA in more than one way, where a "strong" way is of an intercalative nature. Thus, the obtained values of K revealed, that EtBr may interact both with ds-and ss-sites of DNA Vardevanyan et al, 2001). It is reasonable to assume that a non-fluorescent strong complex both with ds-, and ss-DNA is formed by partial intercalation of EtBr molecules into a plane of the neighbor bases of one strands of DNA.…”

“…It indicates that during the denaturation of DNA there is a redistribution of ligand molecules from denatured (ssDNA) on native (not denatured yet-dsDNA) sites, as it takes place at thermo-induced transition . It is necessary also to note that the curves of transition of complexes are shifted in the range of low values of pH in comparison with the curve of DNA itself, that shows a stabilizing effect of EtBr on ds-structure of DNA (see the works (Cantor and Schimmel, 1980;Vardevanyan et al, 2001). Thus, complete denaturation of DNA and its complexes with EtBr occurs at pH = 3.0 and t = 25 o C. For the estimation of EtBr interaction with DNA the suitable values are the binding constant (K) and number of binding site (n).…”

Melting of complexes of DNA-cis-DDP in acidic environment

“…Ionic strength (µ) of [Na + ] was equal to 0.01 (Lando et al, 1994). The melting of DNA and its complexes with cis-DDP carried out on spectrophotometer PYE Unicam-SP 8-100 (England) (Vardevanyan et al, 2001). Speed of scanning of temperature was 0.25 o C/min.…”

Influence of Low Intensity Coherent Electromagnetic Millimeter Radiation (Emr) on Aqua Solution of Dna

“…Melting of each sample of DNA repeated 6 times. Melting curves were constructed as it is described in work [14]. Melting parametersTemperature T m and width of melting interval ∆T of each DNA were averaged on six measurements.…”